Kawahara M, Ito T, Suto C, Shibata S, Rikihisa Y, Hata K, Hirai K
Nagoya City Public Health Research Institute, Nagoya 467-8615, Japan.
J Clin Microbiol. 1999 Apr;37(4):1123-9. doi: 10.1128/JCM.37.4.1123-1129.1999.
In metropolitan Tokyo, the Ehrlichia muris seropositivity rate of 24 wild mice was 63% in Hinohara Village, but in the surrounding areas, it was 0 to 5%. This finding suggests that the reservoir of E. muris is focal. Among the 15 seropositive mice, ehrlichiae were isolated from 9 Apodemus speciosus mice and 1 A. argenteus mouse, respectively. Five ehrlichial isolates were obtained from 10 ticks (Haemaphysalis flava) collected in Asuke Town, Aichi Prefecture, where the E. muris type strain had been isolated. These new isolates were compared with the E. muris type strain. The mouse virulence and ultrastructure of the new isolates were similar to those of the type strain, and all of them were cross-reactive with each other, as well as with the type strain, by indirect immunofluorescent-antibody test. The levels of similarity of the base sequences of the 16S rRNA gene of one of the A. speciosus isolates and one of the tick isolates to that of the E. muris type strain were 99.79 and 99.93%, respectively. We suggest that all of these isolates are E. muris; that E. muris is not limited to Eothenomys kageus but infects other species of mice; and that E. muris is present at locations other than Aichi Prefecture. It appears that H. flava is a potential vector of E. muris. Twenty (1%) of 1803 humans from metropolitan Tokyo were found to be seropositive for E. muris antibodies. A serological survey revealed that exposure to E. muris or organisms antigenically cross-reactive to E. muris occurred among dogs, wild mice, monkeys, bears, deer, and wild boars in Gifu Prefecture, nearby prefectures, and Nagoya City, central Japan. However, human beings and Rattus norvegicus rats in this area were seronegative. These results indicate broader geographic distribution of and human and animal species exposure to E. muris or related Ehrlichia spp. in Japan.
在东京都市区，24只野生小鼠的鼠埃立克体血清阳性率在日之原村为63%，但在周边地区为0%至5%。这一发现表明鼠埃立克体的宿主具有局限性。在15只血清阳性小鼠中，分别从9只日本田鼠和1只银色姬鼠中分离出了埃立克体。从爱知县足助町采集的10只蜱（黄褐血蜱）中获得了5株埃立克体分离株，该地区曾分离出鼠埃立克体模式菌株。将这些新分离株与鼠埃立克体模式菌株进行了比较。新分离株的小鼠毒力和超微结构与模式菌株相似，并且通过间接免疫荧光抗体试验，它们彼此之间以及与模式菌株均具有交叉反应性。一只日本田鼠分离株和一只蜱分离株的16S rRNA基因碱基序列与鼠埃立克体模式菌株的相似性水平分别为99.79%和99.93%。我们认为所有这些分离株均为鼠埃立克体；鼠埃立克体不仅限于贺茂田鼠，还感染其他种类的小鼠；并且鼠埃立克体存在于爱知县以外的地区。黄褐血蜱似乎是鼠埃立克体的潜在传播媒介。在东京都市区的1803人中，有20人（1%）被发现鼠埃立克体抗体血清阳性。一项血清学调查显示，在岐阜县、周边各县以及日本中部名古屋市的狗、野生小鼠、猴子、熊、鹿和野猪中，存在对鼠埃立克体或与鼠埃立克体抗原交叉反应的生物体的接触。然而，该地区的人类和褐家鼠血清学检测呈阴性。这些结果表明，在日本，鼠埃立克体或相关埃立克体属物种在地理分布上更为广泛，并且人类和动物均有接触。
